Advice please!!! 2008 Mustang GT. I get a loud tapping sound every time I hit a bump coming from my rear end. Upon examination I could reproduce the sound by sliding the axle in and out as it has about 1/4" play. It was coming from the diff. When I opened the diff I could see that the axle was sliding in and out and tapping against the center pinion shaft causing my tapping sound. When I removed the pinion shaft, I could see evidence of tapping as there was some wearing. It is almost as if the axle is too long. I don't have a clue how to remedy this so any advice would be appreciated.